Solid source precursor delivery system

ABSTRACT

A solid source precursor material is delivered to a deposition chamber in vaporized form by utilizing a solid source precursor delivery system having either single or multiple stations(s) having a collection/delivery reservoir that is an intermediate stage between a solid source reservoir and a processing deposition chamber. Each collection/delivery reservoir transitions between a collection phase of the solid precursor and the delivery stage of the vaporized precursor during the deposition of a film.

FIELD OF THE INVENTION

This invention relates to semiconductor processing and in particular tothe means and methods for solid source precursor delivery forsemiconductor fabrication processes, such as chemical vapor deposition(CVD) and atomic layer deposition (ALD).

BACKGROUND OF THE INVENTION

Chemical vapor deposition (CVD) and atomic layer deposition (ALD)processes are used extensively throughout semiconductor manufacturingfabrication. A commonality between these two processes is the use of agaseous deposition source that enters the processing chamber and thenchemically reacts within the chamber to deposit a desired film on asubstrate assembly, typically a silicon wafer.

Both CVD and ALD processing utilize precursor materials as a source todeposit the required film and these precursors may be in either gas,liquid or solid forms. Many techniques have been developed tosuccessfully delivery a gas or liquid precursor to the processingchamber in a gaseous or vaporized form. The more difficult precursor touse efficiently in the CVD or ALD process is the solid material (orsolid source chemical precursor). The solid source chemical precursormust be converted to a vapor and transported to the processing chamberwhile avoiding significant thermal decomposition during the vaporizationand delivery stage, which are obstacles that have proven difficult toovercome. What is needed is a deposition processing system that providesthe means and method to effectively deliver a solid source chemicalprecursor to a deposition chamber that effectively addresses theobstacles thereof.

SUMMARY OF THE INVENTION

An exemplary implementation of the present invention includes the meansand method of delivering a solid source chemical precursor material to adeposition chamber utilizing a solid source precursor delivery systemhaving a single station of a collection/delivery reservoir that is anintermediate stage between a solid source reservoir and a depositionchamber. The collection/delivery reservoir transitions between acollection phase of the solid precursor and the delivery stage of thevaporized precursor during the deposition of a film.

Another exemplary implementation of the present invention includes themeans and method of delivering a solid source chemical precursormaterial to a deposition chamber utilizing a solid source precursordelivery system having multiple stations, each having acollection/delivery unit, the multiple stations are intermediate stagesbetween a solid source reservoir and a deposition chamber. Eachcollection/delivery unit transitions between a collection phase of thesolid precursor and the delivery stage of the vaporized precursor andcycles back and forth between the collection and delivery stage duringthe deposition of the film.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 depicts a semiconductor deposition processing apparatus utilizinga single station of a collection/delivery reservoir as an intermediatestage between a solid source reservoir and a deposition chamber, wherethe collection/delivery reservoir is in the solid precursor collectionphase.

FIG. 2 depicts a semiconductor deposition processing apparatus utilizinga single station of collection/delivery reservoir as an intermediatestage between a solid source reservoir and a deposition chamber, wherethe collection/delivery reservoir is in the vaporized precursor deliveryphase.

FIG. 3 is a cross-sectional view of a collection/delivery reservoirhaving a fin-shaped structure that allows for an increased amount ofsolid precursor material buildup during the collection phase.

FIG. 4 depicts a semiconductor deposition processing apparatus utilizingmultiple stations, each station having a collection/delivery reservoir(or unit), the multiple stations being intermediate stages between asolid source reservoir and a deposition chamber, where the multiplestations are in the solid precursor collection phase.

FIG. 5 depicts a semiconductor deposition processing apparatus utilizingmultiple stations, each station having a collection/delivery reservoir(or unit), the multiple stations being intermediate stages between asolid source reservoir and a deposition chamber, where the multiplestations alternate between the solid precursor collection phase and thevaporized precursor delivery stage.

DETAILED DESCRIPTION OF THE INVENTION

Specific embodiments of the present invention provide the means and themethods to deliver a solid source precursor material to a processchamber for deposition of a material onto a substrate, such as asemiconductor wafer, for semiconductor fabrication processes, such aschemical vapor deposition (CVD) and atomic layer deposition (ALD).

FIG. 1 depicts an embodiment of a solid source precursor delivery systemof the present invention having a single station collection/deliveryreservoir. A solid source chemical precursor material is held in aholding reservoir that is incased such that the holding reservoir isheated. Source delivery lines, also heated (i.e. heating piping) andinterrupted by several valves, run from the holding reservoir to acollection/delivery reservoir. A processing chamber delivery line (i.e.,heated piping), controlled by a valve, connects between thecollection/delivery reservoir and the processing chamber. Thecollection/delivery reservoir allows for an efficient and controllablemeans to deliver a solid source chemical precursor material to aprocessing chamber in vapor form. An exhaust pump is connected to theprocessing chamber to expel waste from the chamber.

Referring again to FIG. 1, the operation of solid source precursordelivery system begins with the solid source chemical precursorreservoir 10 that contains a solid source precursor 11. The solid sourceprecursor reservoir 11 is heated, by heating elements 12, to atemperature that is sufficiently high enough to cause the precursor tovaporize and yet not allow the vaporized precursor to decompose. Thevaporized particles of the precursor are transported to thecollection/delivery reservoir by way of the source delivery line 13through valves V2 and V3. V1 allows for the addition of a desired gas orgases, such as an inert gas or a deposition gas or a combinationthereof. The source delivery line 13 is heated, by heating elements 14,in the same manner as the solid source precursor reservoir 10 so thatthe precursor remains in the vaporized state (i.e., vaporized particles)upon entering the collection/delivery reservoir station 15. Theuniqueness of the collection/delivery reservoir station 15 allows it tofunction both as a precursor collection reservoir and a precursordelivery reservoir. The collection/delivery reservoir station 15 isarranged such that each end of reservoir 16 is heated, by heatingelements 17. By heating the ends (an entry port and an exit port) of thereservoir 16 the heated precursor is maintained in a vapor phase so thatduring the collection of the precursor, the ends of thecollection/delivery reservoir 16 will not become clogged with precursormaterial.

The collection/delivery reservoir station 15 contains an inner chamber18 that either heats or cools reservoir 16 depending on whether thereservoir 16 is collecting precursor material in solid form ordispensing (or delivering) vaporized precursor material. During theprecursor collection phase, the inner chamber 18 cools the reservoir 16to a temperature that is sufficient to cause the vaporized precursorentering the inner portion of the reservoir 16 controlled by the innerchamber 18 to revert to a solid material (or particles) by collectingthe precursor 23 on the walls of the collection/delivery reservoir 16.

Referring now to FIG. 2, during the precursor delivery phase, the innerchamber 18 heats the inner portion of reservoir 16 to a temperature thatagain sufficiently vaporizes the precursor and yet avoids significantthermal decomposition of the precursor. The vaporized precursor 24 (orvaporized chemical deposition material) is sent to the processingchamber 21, such as a chemical vapor deposition chamber or an atomiclayer deposition chamber, through the precursor delivery line 19 by wayof valve V4. The precursor delivery line 19 is also heated, by heatingelements 20 to a temperature that sufficiently maintains the precursorin a vaporized state and yet avoids significant thermal decomposition ofthe precursor. Excess precursor, deposition gases and excess reactionmaterials then exit the processing chamber 21 through the exhaust pump22.

The timing between the (precursor) collection phase and the (precursor)delivery phase can be adjusted as needed. For example, a singlecollection phase and then a transition to the delivery phase may besufficient to deposit the desired film on a substrate, such as a siliconwafer. In another example, the collection phase and delivery phase maybe cycled back and forth until the desired film is deposited. In thisexample, first the solid precursor 23 would be collected in thecollection/delivery reservoir 16 while the inner chamber 18 sufficientlycools the inner portion of the reservoir 16, then thecollection/delivery reservoir station 15 would cycle to the deliveryphase as the inner chamber 18 heats the inner portion of the reservoir16 to produce the vaporized precursor 24 that is sent to the processingchamber 21. Then the process is cycled to collect more solid precursor,deliver more vaporized precursor and continues until the desired filmthickness is obtained on the wafer.

FIG. 3 shows a cross-section of a fin-structured collection/deliveryreservoir 30 that could be used to efficiently collect the solidprecursor material 32. Buildup of the solid precursor material 32develops on the inner walls of the collection/delivery reservoir 30 aswell as on the fins 31 of the reservoir that extend inwardly from thereservoir walls. Any design of a collection/delivery reservoir may beused, but the preferred collection/delivery reservoir is one thatprovides an enlarged surface area in order to collect a sufficientamount of solid precursor material needed for deposition.

FIG. 4 depicts an embodiment of a solid source precursor delivery systemof the present invention having multiple stations of collection/deliveryreservoirs. As in the single station embodiment the solid sourcechemical precursor material is held in a holding reservoir that isincased such that the holding reservoir is heated. Multiple deliverylines, also heated (i.e., heated piping) and interrupted by severalvalves, run from the holding reservoir to multiple stations, each havinga collection/delivery reservoir (or unit). It is to be noted that inFIG. 4 two separate stations are shown, but more may be added dependingon the number of stations needed to provide an efficient precursorcollection/delivery system for a given precursor. Multiple processingchamber delivery lines (i.e., heated piping) connect between eachstation and rejoin as a single delivery line to the processing chamber(this too could be altered to having multiple delivery lines enteringthe processing chamber). An exhaust pump is connected to the processingchamber to expel waste from the chamber.

Referring again to FIG. 4, the operation of solid source precursordelivery system begins with the solid source precursor reservoir 40 thatcontains a solid source chemical precursor 41. The solid sourceprecursor reservoir 40 is heated, by heating elements 42 to atemperature that is sufficiently high enough to cause the precursor tovaporize and yet not allow the vaporized precursor (or particles) todecompose. The vaporized precursor is transported to each station 46 and52 by way of the precursor delivery lines 44 through valves V2 and V4,and valves V3 and V5, respectively. Gas delivery line 43, by way of V1allows for the addition of a desired gas or gases, such as an inert gasor a deposition gas or a combination thereof, to each station 46 and 52.The precursor delivery lines 44 are heated, by heating elements 45, inthe same manner as the solid source precursor reservoir 40 so that theprecursor remains in the vaporized state (i.e., vaporized particles)upon entering each collection/delivery reservoir. As before, eachstation containing the collection/delivery reservoir is unique in thateach functions both as a precursor collection reservoir and a precursordelivery reservoir. Each collection/delivery reservoir (47 and 53) isarranged such that each end of the reservoir (an entry port and an exitport) is heated, by heating elements 48 and 54. By heating the ends ofeach reservoir 47 and 53, the heated precursor is maintained in a vaporphase so that during the collection of the precursor, the ends of thecollection/delivery reservoir will not become clogged with precursormaterial.

Each collection/delivery reservoir station (46 and 52) contains an innerchamber (49 and 55) that either heats or cools the reservoir (47 and 53)depending on whether the reservoir is collecting precursor material insolid form or dispensing (or delivering) vaporized precursor material.During the precursor collection phase, the inner chamber cools thereservoir to a temperature that is sufficient to cause the vaporizedprecursor entering the inner portion of the reservoir, controlled by theinner chamber to revert to a solid material (or solid particles) bycollecting the precursor (58) on the walls of the collection/deliveryreservoir.

During the delivery phase, the inner chamber heats the inner portion ofthe reservoir to a temperature that again sufficiently vaporizes theprecursor and yet avoids significant thermal decomposition of theprecursor. The vaporized precursor (or vaporized chemical depositionmaterial) is sent to the processing chamber 56, such as a chemical vapordeposition chamber or an atomic layer deposition chamber, through thedelivery line 50 by way of valve V4. The delivery line 50 is alsoheated, by heating elements 51 to a temperature that sufficientlymaintains the precursor in a vaporized state and yet avoids significantthermal decomposition of the precursor. Excess precursor, depositiongases and excess reaction materials then exit the processing chamber 56through the exhaust pump 57.

Having at least two stations of collection/delivery reservoirs isadvantageous as one station can be in the solid precursor collectionphase, while the second station is in the vaporized precursor deliveryphase. For example and referring to FIG. 4, the first and secondstations 46 and 53 are in the collection phase, the operation of whichis described above. At startup, the solid source precursor 41 is heateduntil it reaches the vaporized state and travels through the heateddelivery lines 44, by way of V3 and V5 to enter the first station 46 andby way of V2 and V4 to enter the second station 52. The inner chambers49 and 55 of the collection/delivery reservoirs 47 and 53 of both thefirst and second stations 46 and 52 are cooled to sufficiently collectthe precursor material on the walls of each collection/deliveryreservoir.

Referring now to FIG. 5, the second station 52 is transitioned to thedelivery phase as the inner chamber 55 heats the inner portion of thereservoir 53 to a temperature to sufficiently vaporize the precursormaterial (without decomposing the precursor) and transfers the vaporizedprecursor 59 (a first volume of vaporized precursor) to the processingchamber 56 by way of V6. Once the second station (in the delivery phase)completes delivery of a second volume of vaporized precursor, the firststation transitions to the precursor delivery phase and the secondstation transitions to the collection phase of the solid precursor. Thedeposition process continues as needed by cycling between the first andsecond stations until the desired film thickness is deposited. Asdisclosed previously in the collection phase, the solid precursor wouldbe collected in the collection/delivery reservoir while the innerchamber sufficiently cools the inner portion of the reservoir. Thevaporized precursor delivery phase is accomplished with the innerchamber heating the inner portion of the reservoir to produce thevaporized precursor that is sent to the processing chamber. When eitherstation is in the delivery phase, the pressure of thecollection/delivery reservoir can be monitored to determine whensufficient vaporization of the precursor has been reached. The processis then cycled to collect more solid precursor and deliver morevaporized precursor as needed to meet the required thickness of the filmbeing deposited.

A solid source precursor system utilizing either a single stationcollection/delivery reservoir or multiple stations ofcollection/delivery reservoirs could be used to deposit such films astantalum nitride (TaN) or tantalum oxide (TaO₅) using the solid sourceprecursor of tantalum fluoride (TaF₅) and adding the appropriatedeposition gas, or films, such as hafnium nitride (HfN) or hafniumdioxide (HfO₂) can be deposited by using the solid source precursor ofhafnium chloride (HfCl4) and adding the appropriate gas. Many othersolid source precursors would be successfully delivered to theprocessing chamber using the system and technique of the presentinvention as one skilled in the art would need to determine thetemperatures for each precursor that will maintain the precursor in thesolid state, the vaporization state and thermal decomposition state,using technical information as readily found in technical publicationsas the CRC handbook or chemical company catalogues, such as STREM,ALDRICH, etc.

For example, when using the solid precursor source of pertakisdimethyltantalum Ta(NMe₂)F₅, one will find that the solid-state temperature isless than approximately 90° C., the melting point is approximately 180°C. or greater. The thermal decomposition of Ta(NMe₂)F₅ is based on bothtemperature and time. Ta(NMe₂)F₅ will decompose 3% at a temperaturegreater than 90° C. when heated approximately 6 hour. It is preferredthat the percentage of decomposition that can be tolerated stay around1%, as some decomposition may occur after vaporization begins.

It is to be understood that, although the present invention has beendescribed with reference to a preferred embodiment, variousmodifications, known to those skilled in the art, may be made to thedisclosed equipment and process herein without departing from theinvention as recited in the several claims appended hereto.

1. A deposition material delivery method for a semiconductor fabricationprocess comprising: heating a solid source chemical precursor materialto a boiling phase to form vapor particles thereof; transporting thevapor particles to a collection/delivery reservoir; sufficiently coolingthe collection/delivery reservoir to convert the vapor particles tosolid particles, a buildup of which is collected in thecollection/delivery reservoir; vaporizing the solid particles to form avaporized chemical deposition material by sufficiently heating thecollection/delivery reservoir; and delivering the vaporized chemicaldeposition material directly to a processing chamber.
 2. The method ofclaim 1, further comprising the addition of an inert gas or a depositiongas to the vapor particles.
 3. The method of claim 1, wherein thesemiconductor fabrication process is a chemical vapor depositionprocess.
 4. The method of claim 1, wherein the semiconductor fabricationprocess is an atomic layer deposition process.
 5. The method of claim 1,wherein the transporting of vapor particles comprises transporting thevapor particles via a transport line that is sufficiently heated toprevent the vapor particles from solidifying in the transport line. 6.The method of claim 5, wherein the sufficiently heated transport line isheated to a temperature that avoids significant thermal decomposition ofthe vapor particles.
 7. The method of claim 6, wherein the significantthermal decomposition comprises a decomposition of the vapor particlesof around 1% or less.
 8. A deposition material delivery method for asemiconductor fabrication process comprising: heating a solid sourcechemical precursor material to a boiling phase to form vapor particlesthereof; transporting the vapor particles to multiple stations, eachstation having a collection/delivery unit that operates in a solidprecursor collection phase and a vaporized precursor delivery phase;sufficiently cooling each collection/delivery unit operating in thesolid precursor collection phase to convert the vapor particles to solidparticles, which are collected in at least a first and a second stationof the multiple stations; sufficiently heating each collection/deliveryunit operating in the vaporized precursor delivery phase to vaporize thesolid particles in at least the first and second stations to form firstand second volumes of vaporized deposition material, respectively;delivering the first volume of vaporized chemical deposition materialdirectly to a processing chamber from the first station; delivering thesecond volume of vaporized chemical deposition material directly to aprocessing chamber from the second station while collecting anotherbuildup of solid particles in the first station; and cycling between themultiple stations from a solid precursor collection phase and avaporized precursor delivery phase so that sufficient vaporized chemicaldeposition material is delivered to the processing chamber fordepositing a layer of material on a substrate.
 9. The method of claim 8,wherein the semiconductor fabrication process is a chemical vapordeposition process.
 10. The method of claim 8, wherein the semiconductorfabrication process is an atomic layer deposition process.
 11. Themethod of claim 8, further comprising transporting the vapor particlesvia multiple transport lines that are sufficiently heated to prevent thesource precursor material from solidifying in the transport lines. 12.The method of claim 11, wherein the sufficiently heated transport linesare heated to a temperature that prevents significant thermaldecomposition of the vapor particles.
 13. The method of claim 12,wherein the significant thermal decomposition comprises a decompositionof the vapor particles of around 1% or less.
 14. The method of claim 8,further comprising the addition of an inert gas or a deposition gas tothe vapor particles.
 15. A deposition material delivery method for asemiconductor fabrication process comprising: heating a solid sourcechemical precursor material to a boiling phase to form vapor precursorparticles thereof; transporting the vapor precursor particles tomultiple stations, each station having a collection/delivery unit thatoperates in a solid precursor collection phase or a vaporized precursordelivery phase; and cycling the multiple stations between the solidprecursor collection phase and the vaporized precursor delivery phasesuch that at least one collection/delivery unit is converting the vaporprecursor particles into solid precursor particles and at least onecollection/delivery unit is converting the solid precursor particlesinto a volume of vaporized precursor particles so that a sufficientamount of vaporized precursor particles is delivered to the processingchamber for depositing a layer of material on a substrate.
 16. Themethod of claim 15, wherein the semiconductor fabrication process is achemical vapor deposition process.
 17. The method of claim 15, whereinthe semiconductor fabrication process is an atomic layer depositionprocess.
 18. The method of claim 15, further comprising transporting thevapor precursor particles via multiple transport lines that aresufficiently heated to prevent the vapor precursor particles fromsolidifying in the transport lines.
 19. The method of claim 18, whereinthe sufficiently heated transport lines are heated to a temperature thatprevents significant thermal decomposition of the vapor precursorparticles.
 20. The method of claim 19, wherein the significant thermaldecomposition comprises a decomposition of the vapor particles of around1% or less.
 21. The method of claim 15, further comprising the additionof an inert gas or a deposition gas to the vapor precursor particles.22. A method for depositing a film on a substrate using a solid sourceprecursor during semiconductor fabrication process comprising: heating asolid source precursor to a boiling phase to form vapor particlesthereof; transporting the vapor particles to a collection/deliveryreservoir; sufficiently cooling the collection/delivery reservoir toconvert the vapor particles to solid particles, a buildup of which iscollected in the collection/delivery reservoir; sufficiently heating thecollection/delivery reservoir to convert the solid particles tore-vaporizing particles; delivering the re-vaporized particles directlyto a processing chamber while avoiding decomposition thereof; anddepositing the film on the substrate.
 23. The method of claim 22,wherein the semiconductor fabrication process is a chemical vapordeposition process.
 24. The method of claim 22, wherein thesemiconductor fabrication process is an atomic layer deposition process.25. The method of claim 22, wherein transporting the vapor particles toa collection/delivery reservoir comprises a transport line that issufficiently heated to prevent the vapor particles from solidifying inthe transport line.
 26. The method of claim 25, wherein the sufficientlyheated transport line is heated to a temperature that preventssignificant thermal decomposition of the vapor particles.
 27. The methodof claim 26, wherein the significant thermal decomposition comprises adecomposition of the vapor particles of around 1% or less.
 28. A solidsource precursor delivery system for a semiconductor fabrication processcomprising: a solid source precursor reservoir; a processing chamber;and a collection/delivery reservoir having an entry port and exit port,the collection/delivery reservoir containing both cooling and heatingelements and connecting between the solid source precursor reservoir andthe processing chamber with heated delivery piping.
 29. The method ofclaim 28, wherein the processing chamber is a chemical vapor depositionchamber.
 30. The method of claim 28, wherein the processing chamber isan atomic layer deposition chamber.
 31. The system of claim 28, furthercomprising heating elements located around the entry port and the exitport such that the temperature of the entry port and the temperature ofthe exist port are separately controllable from the collection/deliveryreservoir.
 32. The system of claim 28, wherein the collection/deliveryreservoir has an inner fin-shaped cross-section.
 33. A solid sourceprecursor delivery system for a semiconductor fabrication processcomprising: a solid source precursor reservoir; a processing chamber;and multiple stations, each station having a collection/deliveryreservoir with an entry port and exit port, each collection/deliveryreservoir containing both cooling and heating elements and connectingbetween the solid source precursor reservoir and the processing chamberwith heated delivery piping.
 34. The method of claim 33, wherein theprocessing chamber is a chemical vapor deposition chamber.
 35. Themethod of claim 33, wherein the processing chamber is an atomic layerdeposition chamber.
 36. The system of claim 33, further comprisingheating elements located on each entry port and each exit port such thatthe temperature of each entry and the temperature of exist port areseparately controllable from a respective collection/delivery reservoir.37. The system of claim 33, wherein each collection/delivery reservoirhas an inner fin-shaped cross-section.